Mould-closing unit for an injection moulding machine

ABSTRACT

A mold-closing unit for an injection molding machine for processing plasticizable masses includes a support element for supporting a piston-cylinder unit for moving a mobile mold carrier and to support a pressure cylinder, and a hydraulic block to supply hydraulic lines inside the support element. The support element has at least two support sections which accommodate between them the hydraulic block and are connected to the hydraulic block via a fastener. Thus the mold-closing unit can be constructed more compactly, with shortening of the bores for the hydraulic lines.

TECHNICAL FIELD

The invention relates to a mold-closing unit for an injection moldingmachine for processing plastics materials and other plasticizable massessuch as e.g. plastics materials, powdery masses or ceramic masses.

BACKGROUND OF THE INVENTION

A mold-closing unit of this kind is known from DE 43 40 693 C2 andserves substantially to move the mobile mold carrier towards thestationary mold carrier in order thereby to close the mold. Apart fromthe piston-cylinder unit necessary for this movement, two pressurecylinders are also provided there to build up the locking pressureduring the injection process. In order to render possible a centralarrangement of the hydraulic block, without additional lines having tobe led to the individual consumers, the support element for themold-closing unit is inserted there simultaneously as a distributor forthe hydraulic medium. In order, however, not to disrupt there thesupport effect of the support element, there is allocated to the supportelement a separate hydraulic block which is disposed on the supportelement. In order, therefore, to make distribution of the hydraulicmedium possible, comparatively long bores are necessary inside thesupport element.

SUMMARY OF THE INVENTION

Proceeding from this prior art, the object underlying the presentinvention is to develop a mold-closing unit of the type mentionedinitially in such a way that a more compact construction of themold-closing unit is realized with shortening of the bores for thehydraulic lines.

This object is achieved by a mold-closing unit with the features ofclaim 1.

Now the support element of the mold-closing unit consists of a pluralityof support sections which accommodate the hydraulic block between them.In order to achieve nevertheless a certain inner stability, the supportsections and the hydraulic block are connected to one another viafastening means. The support sections themselves can be configured moresimply in that only functional bores, i.e. bores which are actuallyrequired for the transmission of hydraulic medium, have to be introducedsince, as a result of the smaller dimensions, correspondingly precisebores can also be bored from one side only. With the arrangement of thehydraulic block between the two support sections, not only can flexiblelines be dispensed with, but the latter can also be shortened; both ofthese being advantages which have a positive effect on the control ofthe mold-closing unit. The break-up of the previous support element,however, also makes possible the use of different materials for the moreseverely loaded support sections and the generally less stressedhydraulic block. The materials can, therefore, be paired with oneanother from the viewpoints of simplification of manufacture and ofstatic dimensioning. Simultaneously, through this distribution, thepre-requisites for increased modularity are created using one and thesame hydraulic distributor in conjunction with support sections of themost varied kind.

If the support sections, in an embodiment according to claim 3, aredesigned symmetrically, this also contributes to increasing modularity,since identically constructed simple parts can be exchanged asnecessary. Simultaneously the transporting of replacement parts is madesimpler even to distant countries.

In an embodiment according to claims 4 and 5, a flow of force arisessuch that forces are substantially transmitted inside the respectiveconnecting section, without there being any more serious stressing inthe region of the hydraulic block on which forces impinge possibly in anembodiment of the balancing cylinder according to claim 8.

The desired modularity can, in an embodiment according to claim 6, befurther increased in that the hydraulic block has at its disposalconnecting regions which co-operate with connecting regions of theconnecting sections, the appearance of the connecting sections in otherrespects being unimportant. Thus the hydraulic block fits with anyconnecting section insofar as the latter only has the suitableconnecting region, which both reduces costs of production and alsocontributes to reducing storage at the manufacturers in respect of thehydraulic block.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 a side view of the mold-closing unit disposed on a machine base,

FIG. 2 a plan view, partially in section, of support element and mobilemold carrier,

FIG. 3 an enlarged detail, partially in section, from FIG. 3 in theregion of the support element,

FIG. 4 a view of the support element according to FIG. 1, from the left,

FIG. 5 a view of the mold-closing unit according to FIG. 1 from the leftand with support section swung out.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is now explained in greater detail, by way of example,with reference to the attached drawings. However the embodiments areonly examples which are not intended to limit the inventive idea to aspecific physical arrangement.

FIG. 1 shows the mold-closing unit located on a machine base 10. Themold-closing unit comprises a stationary mold carrier 11, a mobile moldcarrier 12 and a support element 22 which, in the present case, areconnected via fastening means to the machine base. Mobile mold carrier12 and stationary mold carrier 11 form between them a mold tenteringspace F to accommodate a mold 16. Via a recess 11 a in the stationarymold carrier 11, a plasticizable mass, such as e.g. plastics material ora powdery or ceramic mass can be injected into the closed mold 16 froman injection molding unit which is not shown in the drawings.

Support element 22, mobile mold carrier 12 and stationary mold carrier11 are penetrated by bars 13, which preferably serve to guide a movementunit B (FIG. 2) incorporating the mobile mold carrier 12. During themovement of the mobile mold carrier 12 in and out of the closed positionof the mold, the mold carrier is in addition guided on a guideway 17.Instead of the bars 13, there is in principle also the possibility ofproviding, in a known manner, force transmission elements in the form ofa C-strap, which guide the forces occurring as the mold is closed andthe locking force is applied, around the mold tentering space F. In thiscase, the bridge 38, which here supports the mold-closing unit on themachine base, is then also designed in such a way that, if possible, noforces are transmitted into the machine base 10 from the mold-closingunit.

FIG. 2 makes clear that at least one pressure cylinder 14, in thisembodiment two pressure cylinders with pressure piss ton 14 a at the endof a piston rod 14 b, are provided to build up the locking pressure.Furthermore, at least one piston-cylinder unit 15 is provided which isresponsible for the closing movement, i.e. for the movement of themobile mold carrier 11 in and out of the closed position of the mold 16in the mold tentering space F. In this embodiment, respectively two bars13 and the piston rod 14 b of the pressure piston 14 a, which rodsimultaneously forms the moving cylinder 15 b of the piston-cylinderunit, are connected to the support element 22 and thus to the two—therecan also be more than two—support sections 22 a, whilst the pressurecylinder 14 and the piston rod 15 c with piston 15 a of thepiston-cylinder unit 15 are connected to the mobile mold carrier 12.Naturally other arrangements are also possible in which moving cylinder15 b and piston rod 14 b are not identical to one another and/or arecoaxial to one another. Pressure cylinders 14 are closed at the rear viaa cylinder cover 18 which is braced via tension rods 19 with the mobilemold carrier 12, such that mobile mold carrier 12, pressure cylinder 14and cylinder cover 18 form a movement unit B. This is moreover togetherwith the functioning of the mold-closing unit shown here, the subjectmatter of DE 43 40 693 C2.

Support element 22 serves to support both the pistoncylinder unit 15 andalso one of the parts of pressure piston 14a or pressure cylinder 14. Tothis extent, the arrangement of piston and cylinder is not significantsuch that their arrangement can basically also be reversed. However,advantageously an arrangement such as is represented in FIG. 2 ispreferred, in which the moving cylinder 15 b is disposed coaxially toand in the piston rod 14 b. There is allocated to support element 22 ahydraulic block 30 to supply hydraulic lines 37 inside the supportelement 22. Support element 22 has at least two support sections 22 a,which accommodate the hydraulic block 30 between them. In order toguarantee reliable support, in this embodiment these support sectionsare connected via fastening means 32 to the hydraulic block 30,centering bushes 33 being provided in the transitional region betweenhydraulic block 30 and support section 22 a. This central arrangementbetween the support sections 22 a contributes to shortening the linelength and also to minimizing the outlay for manufacturing the hydrauliclines inside the support segments 22 a. In principle, what is intendedto be achieved by this is that no flexible lines are necessary and yet,nevertheless, the forces can be reliably transmitted via the supportsections. If however the flow of force is in fact substantially led viathe support sections, less importance can be attached to the type offastening between hydraulic block 30 and support section 22 a, although,even then, care should be taken to avoid flexible lines, which basicallycontribute to impairing the control accuracy of the mold-closing unit.

According to FIGS. 3 and 4, the support sections 22 a are disposedsymmetrically to a vertical plane e-e laid through the closing axis s-s.Preferably, the hydraulic lines 37 are also symmetrical to this plane(FIG. 3). There is allocated to each support section 22 a a pressurecylinder 14 and a piston-cylinder unit 15, arrangements being alsopossible here in which e.g. respectively a pressure cylinder isassociated with each of respectively two of four support sections 22 aand a piston-cylinder unit 15 is associated with the other two supportsections 22 a. In this embodiment, each of the two support section 22 ais connected to two bars 13 and the piston rod 14 b of the pressurepiston 14 a, which rod is simultaneously the moving cylinder 15 b of thepistoncylinder unit 15. This arrangement contributes to enabling theflow of force to be kept substantially inside the individual supportsection on the left and the right of the hydraulic block 30. Thehydraulic block 30 is therefore only subject to stress from thebalancing piston-cylinder unit 20 disposed below the pressure cylinders14. According to FIG. 4, the hydraulic block 30 has on both sidesconnecting regions 30 a, at which it is connected to correspondingconnecting regions 22 b of the support sections 22 a. If theseconnecting regions are matched to one another, the appearance of thesupporting sections 22 a in other respects is unimportant, such that oneand the same hydraulic block can be used in machines of different sizes,which contributes to an increase in the modular construction just asmuch as the identical and simple design of the two support sections 22 athemselves. Connecting region 22 b is located roughly at the level ofthe center between the two bars 13 which abut via supports 13 a againstthe support sections 22 a. The length of this connecting region 22 b ina vertical direction is less than two-thirds of the spacing between thecenters of the bars 13. Thus it is possible to provide in the regionabove the connecting regions space for additional hydraulic blocks 34,if e.g. additional functions such as core pullers are to be provided.The view according to FIG. 4 clarifies moreover the arrangement of thehydraulic circuit elements 31 behind the hydraulic block 30.

In principle, leakages can also occur between hydraulic block 30 andsupport sections 22 a. In order to guarantee easier access here in thecase of maintenance, the support section 22 a can, however, be pivotedaround a bar 13 as pivot axis, as shown in FIG. 5. For this purpose, itis necessary to detach the piston rod fastenings 35 of piston rod 14 band remove them from bores 35′ (FIG. 5). In addition, the upper bar 13must be pulled back such that with corresponding slackening in theregion of the lower bar, swiveling out is made possible.

It goes without saying that this specification can be subjected to themost varied modifications, alterations and adaptations which move in theregion of equivalents to the appended claims.

What is claimed is:
 1. A mold-closing unit for an injection moldingmachine for processing plastics materials and other plasticizablemasses, comprising: a stationary mold carrier and a mobile mold carrierwhich form between them a mold tentering space; at least one pressurecylinder with a pressure piston and a piston rod to build up a moldlocking pressure; at least one piston-cylinder unit to move the mobilemold carrier in and out of a closed position of a mold in the moldtentering space; at least one support element to support thepiston-cylinder unit and piston rod or pressure cylinder, hydrauliclines being provided in the support element; and a hydraulic block,allocated to the support element, to supply the hydraulic lines withhydraulic medium, wherein the support element has at least two supportsections which accommodate between them the hydraulic block and areconnected to the hydraulic block via fastening means.
 2. Themold-closing unit according to claim 1, wherein the support sections arepenetrated by at least two bars, which simultaneously serve as guidesfor a movement unit incorporating the mobile mold carrier.
 3. Themold-closing unit according to claim 1, wherein the support sections aredisposed symmetrically to a vertical plane laid through a closing axis,the hydraulic lines being disposed symmetrically to the vertical plane.4. The mold-closing unit according to claim 1, wherein there isallocated to each support section a pressure cylinder and/or apiston-cylinder unit.
 5. The mold-closing unit according to claim 4,wherein said at least two bars and the piston rod of the pressure pistonare connected to each of the two support sections, the piston rodforming simultaneously a moving cylinder of the piston-cylinder unit,the moving cylinder being disposed coaxially to and within the pistonrod.
 6. The mold-closing unit according to claim 2, wherein thehydraulic block has on both sides connecting regions which co-operatewith corresponding connecting regions of the support sections.
 7. Themold-closing unit according to claim 6, wherein the connecting region ofthe support sections is disposed roughly at a level of a center betweenthe two bars per side of the mold-closing unit and a length of theconnecting region in a vertical direction amounts to less thantwo-thirds of a spacing between the centers of the bars.
 8. Themold-closing unit according to claim 1, wherein the support sections maybe swiveled out for maintenance purposes, using a bar as the pivot axis.